In vehicle design, occupant safety is becoming increasingly important. To that end, vehicle safety systems and vehicle structure play a significant role. As a general proposition, when a moving vehicle is abruptly stopped (i.e., from contact with a stationary object or another vehicle), the forward momentum and associated forces are transferred to the vehicle occupants by way of vehicle structure and associated components. To minimize the effects of such forces on vehicle occupants, vehicle safety systems work in conjunction with energy management devices to transfer energy generated by the vehicle impact generally to the structure of the vehicle and away from the vehicle occupants.
Safety systems commonly work in conjunction with vehicle structure to transfer impact forces and divert the associated energy away from the vehicle occupants and into the vehicle structure. Modern vehicle safety systems commonly include a variety of energy management devices such as seatbelts and airbags to help protect a passenger in the event of an impact or accident. Such systems are typically designed to work together with sensors and other structural elements such as door beams, side sill sections, and body panels to improve overall vehicle safety and provide the best possible protection for vehicle occupants. More particularly, such systems act to gradually decelerate the occupants with the vehicle structure to dissipate the forces away from the occupants and into the vehicle structure.
Such impact forces are commonly absorbed by the vehicle structure through deformation of steel and other structural components. In an effort to effectively transmit impact forces to the vehicle structure, vehicle safety systems are implemented to safely transmit the force from a moving occupant (i.e., an occupant moving forward relative to a vehicle structure) to the vehicle structure via an energy management device such as a seatbelt or an airbag. More particularly, the forces associated with an occupant moving relative to the vehicle are safely and controllably transmitted to the vehicle structure via a seatbelt or an airbag such that the structure, as opposed to the occupant, can manage the energy.
Energy management devices, such as airbags and seatbelts, are commonly designed to be used in conjunction with one another to transfer impact forces to the associated vehicle structure. Airbags are generally operable to transmit a force received by a moving occupant to the vehicle structure, while seatbelts are operable to transmit similar forces to the vehicle structure via a vehicle floor pan or vehicle seat, depending on the particular application. As can be appreciated, such vehicle seats are operable to receive the impact force from one of, or both, the airbag and seatbelt to dissipate energy safely to the vehicle structure, thereby protecting the vehicle occupants.
In addition to the aforementioned safety systems, vehicle seats also play a significant role in occupant protection. As can be appreciated, vehicle seats are commonly designed to work with safety systems and energy management devices to divert impact forces into the vehicle structure and away from vehicle occupants.
Conventional seat assemblies commonly include a seatback pivotably supported by a seat bottom and a recliner mechanism. The recliner mechanism is disposed between the seatback and the seat bottom and is operable to selectively position the seatback relative to the seat bottom. In this manner, the ability of the seatback to absorb and transfer forces to a vehicle structure includes at least two components. First, the overall strength of the seatback structure must be of sufficient rigidity to receive a force from an occupant and transfer the associated force to the vehicle structure, and second, the recliner mechanism must be able to transmit such forces from the seatback to the seat bottom and associated vehicle structure. In this regard, interaction between the occupant and the seatback plays a role in energy management during an impact event.
To ensure adequate engagement with a vehicle occupant, conventional vehicle seats commonly include a headrest assembly. Typical headrest assemblies are disposed at an opposite end of the seatback from the recliner mechanism and are operable to receive an occupant's head during normal driving conditions as well as during an impact event. Such headrest assemblies typically provide the occupant with the ability to adjust the position of the headrest relative to the seatback so as to provide each individual occupant with a desirable and comfortable headrest position. As can be appreciated, such an adjustment provides the occupant with the ability to adjust the headrest so as to increase the comfort of the seat assembly under normal driving conditions both axially (i.e., up and down) and in a fore-aft direction. In addition, the adjustment provides the occupant with the ability to adjust the headrest in response to rotation or reclining of the seatback relative to the seat bottom.
Forward adjustment of the headrest upon rearward recline of the seatback relative to the seat bottom helps to ensure that the occupant's head is in close proximity to the headrest at all times. Specifically, under normal driving conditions, positioning of the headrest in such a fashion helps support the occupant's head, thereby providing the occupant with increased comfort. Under an impact event, positioning the headrest in proximity to the occupant's head encourages the occupant to engage the headrest shortly after the initial impact, thereby quickly and efficiently transmitting the impact force from the occupant into the vehicle seat. As previously discussed, such energy management allows the seat assembly and associated vehicle structure to dissipate the impact force and protect the occupant.